#!/usr/bin/env python3

import argparse
import os
import re
import site
import shutil
import subprocess
import tempfile


SCRIPTDIR = os.path.abspath(os.path.dirname(__file__))


def prepend_env_var(env, var, value):
    env[var] = os.pathsep + value + os.pathsep + env.get(var, "")
    env[var] = env[var].replace(os.pathsep + os.pathsep, os.pathsep).strip(os.pathsep)


def get_subprocess_env(options):
    env = os.environ.copy()

    PATH = env.get("PATH", "")
    subprojects_path = os.path.join(options.builddir, "subprojects")
    for proj in os.listdir(subprojects_path):
        projpath = os.path.join(subprojects_path, proj)
        if not os.path.exists(projpath):
            print("Subproject %s does not exist in %s.,\n"
                  " Make sure to build everything properly "
                  "and try again." % (proj, projpath))
            exit(1)

        toolsdir = os.path.join(projpath, "tools")
        if os.path.exists(toolsdir):
            prepend_env_var(env, "PATH", toolsdir)

        prepend_env_var(env, "GST_PLUGIN_PATH", projpath)

    prepend_env_var(env, "GST_PLUGIN_PATH", os.path.join(SCRIPTDIR, 'subprojects',
                                                         'gst-python', 'plugin'))
    env["CURRENT_GST"] = os.path.normpath(SCRIPTDIR)
    env["GST_VALIDATE_SCENARIOS_PATH"] = os.path.normpath(
        "%s/subprojects/gst-devtools/validate/data/scenarios" % SCRIPTDIR)
    env["GST_VALIDATE_PLUGIN_PATH"] = os.path.normpath(
        "%s/subprojects/gst-devtools/validate/plugins" % options.builddir)
    env["GST_VALIDATE_APPS_DIR"] = os.path.normpath(
        "%s/subprojects/gst-editing-services/tests/validate" % SCRIPTDIR)
    prepend_env_var(env, "PATH", os.path.normpath(
        "%s/subprojects/gst-devtools/validate/tools" % options.builddir))
    prepend_env_var(env, "PATH", os.path.join(SCRIPTDIR, 'meson'))
    env["PATH"] += os.pathsep + PATH
    env["GST_VERSION"] = options.gst_version
    env["GST_ENV"] = 'gst-' + options.gst_version
    env["GST_PLUGIN_SYSTEM_PATH"] = ""
    env["GST_PLUGIN_SCANNER"] = os.path.normpath(
        "%s/subprojects/gstreamer/libs/gst/helpers/gst-plugin-scanner" % options.builddir)
    env["GST_PTP_HELPER"] = os.path.normpath(
        "%s/subprojects/gstreamer/libs/gst/helpers/gst-ptp-helper" % options.builddir)
    env["GST_REGISTRY"] = os.path.normpath(options.builddir + "/registry.dat")

    filename = "meson.build"
    sharedlib_reg = re.compile(r'\.so$|\.dylib$')
    typelib_reg = re.compile(r'.*\.typelib$')
    for root, dirnames, filenames in os.walk(os.path.join(options.builddir,
                                                          'subprojects')):
        has_typelib = False
        has_shared = False
        for filename in filenames:
            if typelib_reg.search(filename) and not has_typelib:
                has_typelib = True
                prepend_env_var(env, "GI_TYPELIB_PATH",
                                os.path.join(options.builddir, root))
                if has_shared:
                    break
            elif sharedlib_reg.search(filename) and not has_shared:
                has_shared = True
                prepend_env_var(env, "LD_LIBRARY_PATH",
                                os.path.join(options.builddir, root))
                prepend_env_var(env, "DYLD_LIBRARY_PATH",
                                os.path.join(options.builddir, root))
                if has_typelib:
                    break

    return env


def python_env(options, unset_env=False):
    """
    Setup our overrides_hack.py as sitecustomize.py script in user
    site-packages if unset_env=False, else unset, previously set
    env.
    """
    subprojects_path = os.path.join(options.builddir, "subprojects")
    gst_python_path = os.path.join(SCRIPTDIR, "subprojects", "gst-python")
    if not os.path.exists(os.path.join(subprojects_path, "gst-python")) or \
            not os.path.exists(gst_python_path):
        return False

    sitepackages = site.getusersitepackages()
    if not sitepackages:
        return False

    sitecustomize = os.path.join(sitepackages, "sitecustomize.py")
    overrides_hack = os.path.join(gst_python_path, "testsuite", "overrides_hack.py")

    if not unset_env:
        if os.path.exists(sitecustomize):
            if os.path.realpath(sitecustomize) == overrides_hack:
                print("Customize user site script already linked to the GStreamer one")
                return False

            old_sitecustomize = os.path.join(sitepackages,
                                            "old.sitecustomize.gstuninstalled.py")
            shutil.move(sitecustomize, old_sitecustomize)
        elif not os.path.exists(sitepackages):
            os.makedirs(sitepackages)

        os.symlink(overrides_hack, sitecustomize)
        return os.path.realpath(sitecustomize) == overrides_hack
    else:
        if not os.path.realpath(sitecustomize) == overrides_hack:
            return False

        os.remove(sitecustomize)
        old_sitecustomize = os.path.join(sitepackages,
                                            "old.sitecustomize.gstuninstalled.py")

        if os.path.exists(old_sitecustomize):
            shutil.move(old_sitecustomize, sitecustomize)

        return True


if __name__ == "__main__":
    parser = argparse.ArgumentParser(prog="gstreamer-uninstalled")

    parser.add_argument("--builddir",
                        default=os.path.join(SCRIPTDIR, "build"),
                        help="The meson build directory")
    parser.add_argument("--gst-version", default="master",
                        help="The GStreamer major version")
    options, args = parser.parse_known_args()

    if not os.path.exists(options.builddir):
        print("GStreamer not built in %s\n\nBuild it and try again" %
              options.builddir)
        exit(1)

    if not args:
        if os.name is 'nt':
            args = [os.environ.get("COMSPEC", r"C:\WINDOWS\system32\cmd.exe")]
        else:
            args = [os.environ.get("SHELL", os.path.realpath("/bin/sh"))]
        if "bash" in args[0]:
            bashrc = os.path.expanduser('~/.bashrc')
            if os.path.exists(bashrc):
                tmprc = tempfile.NamedTemporaryFile(mode='w')
                with open(bashrc, 'r') as src:
                    shutil.copyfileobj(src, tmprc)
                tmprc.write('\nexport PS1="[gst-%s] $PS1"' % options.gst_version)
                tmprc.flush()
                # Let the GC remove the tmp file
                args.append("--rcfile")
                args.append(tmprc.name)
    python_set = python_env(options)
    try:
        exit(subprocess.call(args, env=get_subprocess_env(options)))
    except subprocess.CalledProcessError as e:
        exit(e.returncode)
    finally:
        if python_set:
            python_env(options, unset_env=True)